Kidney Glomerulus of Hypertension Produced Experimentally by Pituitary Excess

Abstract

That the thickened basement membrane of glomerular capillaries in hypertension is primarily due to the hypertension itself has not been definitely shown and the suggested relationship of the pituitary to hypertension has been based upon insufficient clinical evidence. The present experiments have produced in the amphibian a condition paralleling hypertension in the mammal with vasoconstriction, slowed heart rate, thickened ventricular wall and edema (Blount 1 ). This has been accomplished by the transplantation of additional pituitary anlagen in the embryo (Blount 2 ) which develop and give a constant excess of hormone secretion bringing about the results described. The constant secretion is indicated by pigmentation changes and vasoconstriction which are maintained. Since this takes place during the development of the structures involved there is an adjustment which tends to establish a balance at the high pituitary level.

The glomerulus of the mesonephros in all the 15 triple pituitary animals examined shows certain changes which are characteristic of the hypertensive glomerulus in man. As shown by either Mallory's stain or by azocarmine the basement membrane of the capillary tuft of the normal animal is roughly 1 to 2 micra thick while that of the triple pituitary animals may exceed 8 micra. This membrane may exhibit lighter areas which appear to be small cracks or pores and is similar to that of hypertension in man especially when associated with lipoid nephrosis. Many of the capillaries are closed. The glomerulus is small in respect to the capsule which it does not fill to the normal degree. There are accompanying changes in the tubules which are associated with glomeruli that are most affected. These changes are progressive with age. The degree of involvement is directly proportional to the amount of pituitary excess as measured by the degree of response in such characters as pigment increase.